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Processing technology of PVC calendered film

by:LINYANG     2022-06-29
Different processing techniques can be used for different films or when producing different products. Under certain conditions of film type, properties and various additives, the influence of processing technology on film performance is very significant. Today, ZHONGSHAN LINYANG PLASTIC CO.LTD will tell you about the processing technology knowledge of PVC calendered film: ( 1) Injection molding: For thermoplastic films, the film particles are heated and melted in an injection molding machine, and injected into the mold at high pressure and speed. (2) Extrusion molding: The heated and melted film is extruded into profiles of different shapes through the extrusion action of the extruder and through different hole-type dies. (3) Spraying process: spray plastic film layer on metal, non-metallic plate surface and fiber mesh tire; (4) Molding: for thermosetting film, put plastic powder, flakes, and granular raw materials into the mold and pressurize when heating and softening (5) Lamination molding: After the layered reinforcing material is dip-coated with thermosetting resin, it is processed into a rotten laminated board, which is then subjected to pressure and heating treatment by a laminator to make it Cured molding. (6) Casting molding: pour the liquid film into the mold, make it solidify and cool under normal pressure or low pressure: (7) Foam molding: mechanical or chemical methods can be used to introduce large and small spherical bubbles into the plastic The foam film is made into a foam film with low bulk density, good thermal insulation performance and good sound absorption performance. Introduction to the physical and mechanical properties of PVC calendered film The physical and mechanical properties of PVC calendered film mainly include the following: (1) Specific strength. Membrane products have higher specific strength than other materials, so they have become the preferred materials in architectural decoration, daily use, aerospace and other projects. (2) Insulation. The conductivity of membrane products is smaller than that of metal or rock, that is, the ability of heat conduction, electrical conduction and wave conduction is small, so its thermal conductivity is small (1/500-1/600 of metal), electrical insulation, vibration damping and sound absorption. Good (3) usability. The decorative availability of film products is good: first. The plastic products are colorful and rich, the surface is smooth and lustrous, the product pattern is clear, the straight and curved lines are straight and square, and the curve is soft and beautiful. Fast and convenient, thermoplastics can also be bent and reshaped, and the quality of decorative construction is easy to ensure. In addition, plastic products are resistant to acid, alkali, salt and water erosion, and have good chemical stability, so they are beautiful and durable. Non-foaming products are easy to clean and paint. (4) Thermal properties. Compared with other building decoration materials, the materials have unique thermal deformation properties. When plastic is heated, its deformability increases, resulting in fluidity; this phenomenon is called softening. The temperature at which the material is softened to a certain degree under a certain load - the heat-resistant temperature table - the heat-resistant temperature of thermoplastics is 5 () to 90 °C, and the heat-resistant temperature of thermal plastics is 100 to 200 °C. When the humidity of the plastic use environment decreases, its brittleness increases, and when subjected to mechanical impact, it is easily broken and damaged. The cold brittleness of small films is measured by embrittlement temperature. In addition, the thermal expansion coefficient of the film is relatively large, which is about 3 times that of the metal material. Pay attention to the design of the blending modification formula of the PVC calendered film. The design of the formula is an important step in the forming process of the calendered film, especially for the PVC calendered film. In order to improve the molding properties of the PVC calendered film, the stability of the material, obtain products with good performance and reduce the cost, various additives must be added to the PVC calendered film. Rigid PVC plastic formulations typically contain the following components. a. Resin The performance of the resin should be able to meet the performance requirements of various processing and final products. The resin used for rigid PVC calendering film is usually a suspended loose resin with an absolute viscosity of 1.5-1.8mPas. b. Stabilizer The addition of stabilizer can prevent the degradation of PVC calendered film during high temperature processing and deteriorate the performance. The stabilizers used in PVC formulations are usually divided into four categories according to chemical components: lead salts, barium salts, metal soaps , Organotin, epoxy lipids and rare earths. c Lubricant The main function of the lubricant is to prevent the adhesion of metal, delay the gelation of PVC and reduce the melt degree. Lubricants can be divided into two categories: external lubricants and internal lubricants. It can be OP wax, PE wax, etc. d. Fillers Adding fillers to PPVC calendered films can greatly reduce product costs and improve certain properties of the products. Commonly used fillers are CaCO3, BaS04, etc. e. In order to improve the shortcomings of poor processability, thermal stability, heat resistance and impact resistance of PVC calendered film as a rigid plastic, various modifiers are often added as required. The modifiers mainly include the following categories: 1. Impact modifier - used to improve the impact resistance and low temperature brittleness of PVC, commonly used are chlorinated polyethylene (CPE), ethylene-vinyl acetate copolymer (EVA, acrylic copolymer (ACR), propylene resin -Butadiene-styrene (ABS) and methyl methacrylate-butadiene-styrene branched copolymer, etc. 2. Processing modifier - its function only improves the processing performance of the material without significantly reducing or Substances that damage other physical properties, commonly used processing modifiers such as acrylates, acrylic esters and styrene copolymers, etc. 3. Deformation modifiers—used to improve the thermal deformation temperature of products under load, commonly used in acrylic acid blends Styrene copolymer. In addition, pigments, flame retardants and foaming agents are added as needed. The functions of the prepared components in the formulation of PVC calendered film are interrelated and cannot be selected in isolation. Fully consider the factors of preparation, and design according to the performance requirements of different products, source of raw materials, price and molding process.
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